The aim of this study was to evaluate the in vivo response of different fluences of low-level laser therapy (LLLT) on the area of the injury, inflammatory markers, and functional recovery using an experimental model of traumatic spinal cord injury (SCI). Thirty two rats were randomly divided into four experimental groups: control group (CG), laser-treated group 500 J/cm(2) (L-500), laser-treated group 750 J/cm(2) (L-750), and laser-treated group 1000 J/cm(2) (L-1000). SCI was performed by an impactor equipment (between the ninth and tenth thoracic vertebrae), with a pressure of 150 kdyn. Afterwards, the injured region was irradiated daily for seven consecutive sessions, using an 808-nm laser, at the respective fluence of each experimental groups. Motor function and tactile sensitivity were performed on days 1 and 7 post-surgery. Animals were euthanized on the eighth day after injury, and the samples were retrieved for histological and immunohistochemistry analyses. Functional evaluation and tactile sensitivity were improved after LLLT, at the higher fluence. Additionally, LLLT, at 750 and 1000 J/cm(2), reduces the lesion volume and modulates the inflammatory process with decrease of CD-68 protein expression. These results suggest that LLLT athigher doses was effective in promoting functional recovery and modulating inflammatory process in the spinal cord of rats after SCI.

INTRODUCTION:This meta-analysis investigated the effectiveness of low-level laser therapy (LLLT) on pain in adult patients with musculoskeletal disorders.

EVIDENCE ACQUISITION:A systematic literature search was conducted in the Medline and PEDro databases. Two researchers independently screened titles and abstracts of the retrieved studies for eligibility. Quality assessment of the eligible studies was conducted using the PEDro rating scale. Studies that scored≥ 4 were included. A random-effects model was used for this meta-analysis. Subgroup meta-analyses were conducted to evaluate the influence of the adherence of the applied LLLT to the World Association of Laser Therapy (WALT) guidelines, the anatomical site under investigation and the study designon the overall weighted mean effect size. Meta regression was used to assess the possible influence of the study quality on the individual study effect sizes.

EVIDENCE SYNTHESIS:Eighteen studies allowing for 21 head-to-head comparisons (totaling n=1462 participants) were included. The pooled raw mean difference (D) in pain between LLLT and the control groups was -0.85 [95%CI: -1.22 to -0.48]. There was high (I² = 85.6%) and significant between study heterogeneity (Cochran's Q = 139.2; df = 20; p<0.001). The subgroup meta-analysis of the comparisons not following the WALT guidelines revealed a D = -0.68 [95%CI: -1.09 to -0.27]. In this group, heterogeneity decreased to I² = 72.6% (Q = 51.2; df = 14; p<0.001). In the WALT subgroup D equaled -1.52 [95%CI: -2.34 to -0.70]. this between groups difference was clinically relevant although statistically not significant (Q = 3.24; df = 1; p = 0.072).

CONCLUSIONS:This meta-analysis presents evidence that LLLT is an effective treatment modality to reduce pain in adult patients with musculoskeletal disorders. Adherence to WALT dosage recommendations seems to enhance treatment effectiveness.

Phototherapy has demonstrated positive effects in the treatment of peripheral nerve injury, but there is a need to investigate the dosimetric parameters. Thus, the aim of the present study was to conduct a literature review on the effects of photobiomodulation with the use of low-level laser therapy (LLLT) on the treatment of peripheral nerve injury in experimental models. The databases of PubMed/MEDLINE, SCOPUS, and SPIE Digital Library were searched for articles on the use of LLLT in experimental models of peripheral nerve injury published in English between January 2007 and March 2016. The laser parameter variability was wavelength (632.8 to 980 nm), power (10 to 190 mW), and total energy (0.15 to 90 J) in pulsed or continuous wave and single or multiple points. Eighteen original articles demonstrating the effects of LLLT on the acceleration of functional recovery, morphological aspects as well as the modulation of the expression inflammatory cytokines, and growth factors were selected. LLLT is a viable phototherapeutic modality for the treatment of peripheral nerve injury, demonstrating positive effects on the neuromuscular repair process using either red or infrared light. The majority of studies used a power of up to 50 mW andtotal energy of up to 15 J administered to multiple points. The determination of these parameters is important to the standardization of a LLLT protocol to enhance the regeneration process following a peripheral nerve injury.

BACKGROUND:Burning mouth syndrome (BMS) is a chronic pain condition with indefinite cure, predominantly affecting post-menopausal women. The aim of this study was to systematically review the efficacy of low level laser therapy in the treatment of burning mouth syndrome (BMS).

METHODS:PubMed, Embase and Scopus were searched from date of inception till and including October 2016 using various combinations of the following keywords: burning mouth syndrome, BMS, stomatodynia, laser therapy, laser treatment and phototherapy. The inclusion criteria were: Prospective, retrospective and case series studies. Letter to editors, reviews, experimental studies, studies that were not published in English, theses, monographs, and abstracts presented in scientific events were excluded. Due to heterogeneity of data no statistical analyses were performed.

RESULTS:Ten clinical studies fulfilled the eligibility criteria, five of which were randomized clinical trials. In these studies, the laser wavelengths, power output and duration of irradiation ranged between 630- 980nm, 20-300mW, 10 seconds-15minutes, respectively. Most of studies reported laser to be an effective therapy strategy for management of BMS.

CONCLUSION:Majority of the studies showed that laser therapy seemed to be effective in reducing pain in BMS patients. However, due to the varied methodologies and substantial variations in laser parameters among these studies, more clinical trials are required to ascertain the efficacy of laser for treating BMS.

Low energy lasers are widely used to treat a variety of musculoskeletal conditions including fibromyalgia, despite the lack of scientific evidence to support its efficacy. A randomised, single-blind, placebo-controlled study was conducted to evaluate the efficacy of low-energy laser therapy in 40 female patients with fibromyalgia. Patients with fibromyalgia were randomly allocated to active (Ga-As) laser or placebo laser treatment daily for two weeks except weekends. Both the laser and placebo laser groups were evaluated for the improvement in pain, number of tender points, skinfold tenderness, stiffness, sleep disturbance, fatigue, and muscular spasm. In both groups, significant improvements were achieved in all parameters (p<0.05) except sleep disturbance, fatigue and skinfold tenderness in the placebo laser group (p>0.05). It was found that there was no significant difference between the two groups with respect to all parameters before therapy whereas a significant difference was observed in parameters as pain, muscle spasm, morning stiffness and tender point numbers in favour of laser group after therapy (p<0.05). None of the participants reported any side effects. Our study suggests that laser therapy is effective on pain, muscle spasm, morning stiffness, and total tender point number in fibromyalgia and suggests that this therapy method is a safe and effective way of treatment in the cases with fibromyalgia.

OBJECTIVE AND BACKGROUND:Tinnitus is an apparent sound, perceived in the ear with no stimulus. It has been described as a sound originating from the brain. It affects 17% of the general population. Etiological factors for tinnitus include temporomandibular joint disorders (TMJ, TMD) and Costen's syndrome. The aim of treatment is to eliminate the tinnitus or at least decrease its apparent volume.

MATERIALS AND METHODS:In total, 46 patients referred to our department with bilateral subjective tinnitus with TMDs were selected for this study. Low-level laser therapy (LLLT) with an neodymium-doped yttrium aluminum garnet (Nd:YAG) (1064 nm) laser, LLLT with a diode laser (810 nm), and placebo treatment were applied to the patients. There were 15 patients each in the Nd:YAG and placebo groups and 16 patients in the 810 nm diode laser group. LLLT was applied for 10 days, once per day. A visual analog scale (VAS) was used, withvalues between 0 and 10. VAS scores were recorded before treatment, on the last day of treatment, and 1 month after treatment. The VAS scores were the same on the last day of treatment and 1 month after treatment. The VAS scores before treatment and at 1 month after treatment were compared in a statistical analysis.

RESULTS:There were statistically significant differences in the Nd:YAG laser (p = 0.001) and 810 nm diode laser groups (p = 0.005), but no difference in the placebo group (p = 0.065).

CONCLUSIONS:Both the Nd:YAG and 810 nm diode lasers were effective for the treatment of subjective tinnitus related to TMDs.

PURPOSE:The aim of this systematic review was to assess the efficacy of low-level laser therapy (LLLT) in patients with temporomandibular disorders (TMDs).

METHODS:Medline search was done from 1997 to 2011 using search terms appropriate to establishing a relation between LLLT and TMD. Only randomized controlled trials were included in this study. Outcome variables related to pain, muscle tenderness, mandibular movements, and Electromyographic (EMG) activity were considered. Of the 242 articles examined, 13 were finally included in the critical analysis conducted as a part of the present systematic review.

RESULTS:Of the 242 titles reviewed, only 13 articles were considered eligible. 7 articles showed significant improvement in the study group, whereas 5 showed no significant improvement between the study and control groups. The primary outcome of most of the studies was pain. Other variables considered were muscle tenderness, mandibular movements; EMG activity was considered.

CONCLUSION:Our results have shown that LLLT seems to be effective in reducing pain in TMD's. It may be a treatment option for patients with an interest in a noninvasive, complementary therapy.

BACKGROUND:The efficacy of photodynamic therapy (PDT) or low level laser therapy (LLLT) in the treatment of oral lichen planus (OLP) is debatable. The aim of this study was to compare the effects of PDT, LLLT or topical corticosteroid application in the treatment of erosive-atrophic OLP.

MATERIALS AND METHODS:Forty-five adult patients with erosive-atrophic biopsy-proven OLP on the tongue or buccal mucosa (size≤3 cm) were randomly divided into three groups. Group-1: patients receiving PDT topical application of 50 μl toluidine blue (1 mg/ml) with micropipette and after 10 min treated by laser irradiation using GaAlAs laser (630 nm, 10 mW/cm, continuous wave, spot size: 1 cm); Group-2: patients receiving LLLT using diode laser (630 nm, 10 mW, continuous wave, spot size: 1 cm); and Group-3: patients receiving topical corticosteroid applications consisting of dexamethasone (0.5 mg in 5 ml water) mouthwash for 5 min. Demographic data, type, and severity of the lesions and pain were recorded before and after treatment and then at the 1 year follow-up.

RESULTS:There was a significant difference in sign score changes before and after the treatment in the PDT group (p = 0.03), LLLT group (p = 0.04) and in the control group (p = 0.02). There was a statistically significant difference between group-1 (p = 0.001) and group-2 (p = 0.001) against group-3 before and after treatment. Mean amount of improvement in pain was significantly greater in the control group in comparison with the PDT and LLLT groups (p < 0.001). The efficacy index of the PDT group improved significantly more than the LLLT (p = 0.001) and corticosteroid groups (p = 0.001).

CONCLUSION:Within the limits of the present RCT, it is indicated that PDT and LLLT are effective in the treatment of erosive-atrophic forms of OLP in adult patients. However, further comparative clinical trials are needed to obtain strong conclusions in this regard.

Diabetic neuropathy (DN) is the highly occurred complication of diabetes mellitus; it has been defined as an event of peripheral nerve dysfunction characterized by pain, allodynia, hyperalgesia, and paraesthesia. The current study was conducted to evaluate the efficacy of low-level laser therapy (LLLT) in the management of neuropathy in diabetic rats. The used animals were divided into the following groups: negative control, streptozotocin-induced diabetic rats, and diabetic rats with peripheral neuropathy (DNP) and DNP treated with gabapentin or with LLLT. Behavioral tests were carried out through hotplate test for the determination of pain sensations and the Morris water maze test for spatial reference memory evaluation. Blood samples were collected at the end of treatment for biochemical determinations. In the current study, the latency of hind-paw lick decreased significantly when DNP are treated with gabapentin or LLLT. The Morris water maze test showed that LLLT treatment improved memory that deteriorated in DNP more than gabapentin do. The results of the biochemical study revealed that LLLT could not affect the level of beta-endorphin that decreased in DNP but significantly decreased S100B that rose in DNP. PGE2 and cytokines IL-1β, IL-10, and TNF-α showed significant increase in DNP compared with control group. The gabapentin administration or LLLT application significantly reversed the levels of the mentioned markers towards the normal values of the controls. Levels of serum MDA and nitric oxide increased significantly in the DNP but rGSH showed significant decrease. These markers were improved significantly when the DNP were treated with gabapentin or LLLT. The treatment with gabapentin or LLLT significantly decreased the raised level in total cholesterol in DNP but could not decrease the elevated level of triglycerides, while LDL cholesterol decreased significantly in DNP treated with gabapentin but not affected by LLLT. Values of serum alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), urea, and creatinine increased significantly in the DPN and diabetic rats without peripheral neuropathy (PN) compared with control group. The treatment of DNP with gabapentin induced significant increases in ALAT and ASAT activities but LLLT treatment induced significant decreases in ALAT and ASAT activities as compared with DNP group. Neither gabapentin nor LLLT could improve the elevated levels of serum urea and creatinine in the DNP. It could be concluded that LLLT is more safe and effective than gabapentin in the management of neuropathy in diabetic rats.

Cytokine proteins may have important roles during different human physiological and pathological processes. In the oral cavity, the bone loss and periodontal tissue pathology was related to inflammatory process activation. The aim of the present study was to assess the effects of etiological periodontal therapy with and without the use of Low Level Laser Therapy (LLLT) on clinical periodontal parameters and interleukin (IL)-1β level in gingival crevicular fluid (GCF) from chronic periodontitis (CP) patients. Thirty non-smoker CP patients were selected from the Foggia University Dental Clinic and other 2 private dental clinics. All patients were divided into two homogeneous randomized groups: 15 patients were treated with only scaling and root planing (group 1) and 15 patients with scaling and root planing etiological treatment and LLLT (group 2). In all sites, at baseline before treatment, the periodontal pocket depth (PPD) and bleeding on probing (BOP) were measured. In the PPD sites, the GCF samples were collected from 30 deep (≥5 mm) and shallow (≤3 mm) sites and IL-1β were evaluated at baseline, after 10 days and 1 month. In all the samples at baseline, the IL-1β concentration in GCF and BOP rate were significantly higher at deep PPD sites than at the shallow ones. After 10 days in all samples noPPD improvement was observed in the BOP rate but the IL-1 β level was statistically significantly improved (p<0.005) in group 2 compared to group 1. At 10 days and 1 month, in all deep PPD sites, PPD and BOP improvements were observed. At same time, IL-1β levels were lower and statistically significantly (p<0.005) improved in group 2 compared to group 1. The results confirmed that the periodontal etiology treatment of deep PPD sites with or with-out associated LLLT promotes periodontal health. Etiological treatment associated with LLLT, improves BOP and inflammation in periodontal disease. Moreover, the IL-1β concentration changes in GCF suggest these cytokines as a predictable marker of gingival inflammation in chronic periodontitis patients.

The aim of this study was to evaluate the efficacy of low-level laser therapy (LLLT) and alpha-lipoic acid (ALA) in the treatment of burning mouth syndrome (BMS) and secondary oral burning (SOB) by unstimulated sialometry, symptom assessment, and measurement of salivary TNF-α levels. Forty-four patients were randomized into four treatment groups: BMS/laser (n = 10), BMS/ALA (n = 5), SOB/laser (n = 15), and SOB/ALA (n = 14). The control group consisted of eight healthy female subjects. Unstimulated salivary flow was measured before and after treatment, andthe collected saliva was stored at - 20 °C for the analysis of TNF-α. Symptoms were evaluated before and after treatment using a pain visual analog scale. Most patients were women (81.8%) during menopause (72.2%). LLLT and ALA were efficient in increasing salivary flow only in BMS but providedsymptom relief in both conditions. TNF-α levels did not differ between patients with BMS and SOB or between those patients and the control group. No differences were observed in posttreatment TNF-α levels in either condition. The results of this study suggest that LLLT and ALA are efficient therapies in reducing burning mouth symptoms, with LLLT being more efficient than ALA.

This study evaluated the effects and mechanism of action of combining irreversible electroporation (IRE) and photodynamic therapy (PDT) in breast cancer cellsand. Jin's formula was used to assess killing efficacy of different IRE+PDT dosing combinations in breast cancer MCF-7 cells. Flow cytometry, high-content imaging, and confocal laser scanning microscopy were used to detect apoptosis. qRT-PCR and western blotting were used to evaluate expression of apoptosis-related genes and proteins. IRE+PDT combination therapy was administered to BALB/C mice with breast cancer tumors in vivo; tumor size was used to assess treatment efficacy. Killing mechanisms were examined using transmission electron microscopy and immunohistochemistry. We found that IRE+PDT combination therapy produced significant synergistic killing effects in breast cancer cells (highest Jin q value of 1.32). Early apoptosis rates were significantly higher in the IRE+PDT group (16.0%) than in IRE-alone (7.6%) and PDT-alone (4.6%) groups (<0.05). qRT-PCR showed higher Caspase-1, -3, -5, -6, -7, -8, and -9 and TNFRSF1A expression with IRE+PDT than with control. Western blots showed increased cleaved Caspase-3, -7, and -9, and PARP levels in the IRE+PDT group.tumor suppression rate for IRE (1200 V)+PDT (10 mg/kg) was 68.3%. Combination therapy produced the most obvious apoptosis effects. Compared with controls, the IRE+PDT group exhibited lower new blood vessel (VEGF, CD31), metastasis (TGF-β), and cell proliferation (Ki-67) indicators and higher inflammation indicator (TNF-α) 1 day post-treatment. Thus, combining IRE and PDT enhanced their anti-tumor effects in breast cancer, and apoptosis played a key role in this process.

The purpose of the present work was to study the effect of low-level laser therapy (LLLT): helium-neon (He-Ne) and gallium arsenide (Ga-As) laser on the histomorphology of muscle and mitochondria in experimental myopathy in rats. Thirty Suquía strain female rats were distributed in groups: (A) control (intact), (B) injured, (C) injured and treated with He-Ne laser, (D) injured and treated with Ga-As laser, (E) irradiated with He-Ne laser on the non-injured muscle, and (F) irradiated with Ga-As laser on the non-injured muscle. Myopathywas induced by injecting 0.05 mg/rat/day of adrenaline in the left gastrocnemius muscle at the same point on five consecutive days, in groups B, C, and D. LLLT was applied with 9.5 J cm(-2) daily for seven consecutive days in groups C, D, E, and F. The muscles were examined with optic and electronic microscopy. The inflammation was classified as absent, mild, and intense and the degree of mitochondrial alteration was graded I, II, III, and IV. Categorical data were statistically analyzed by Chi-square and the Fisher-Irwin Bilateral test, setting significant difference at p < 0.05. The damage found in muscle and mitochondria histomorphology in animals with induced myopathy (B) was intense or severe inflammation with grade III or IV of mitochondrial alteration. They underwent significant regression (p < 0.001) compared with the groups treated with He-Ne (C) and Ga-As (D) laser, in which mild or moderate inflammation was seen and mitochondrial alteration grades I and II, recovering normal myofibrillar architecture. No differences were found between the effects caused by the two lasers, or betweengroups A, E, and F. Group A was found to be different from B, C, and D (p < 0.001). LLLT in experimental myopathy caused significant muscular and mitochondrial morphologic recovery.

Late effects of radiotherapy for head and neck cancer treatment have been increasingly investigated due to its impact on patients' quality of life. The purpose of this study was to evaluate the effect of low-level laser therapy on hyposalivation, low salivary pH, and quality of life in head and neck cancer patients post-radiotherapy. Twenty-nine patients with radiation-induced xerostomia received laser sessions twice a week, during 3 months (24 sessions). For this, a continuous wave Indium-Gallium-Aluminium-Phosphorus diode laser device was used punctually on the major salivary glands (808 nm, 0.75 W/cm(2), 30 mW, illuminated area 0.04 cm(2), 7.5 J/cm(2), 10 s, 0.3 J). Six extraoral points were illuminated on each parotid gland and three on each submandibular gland, as well as two intraoral points on each sublingual gland. Stimulated and unstimulated salivary flow rate, pH (two scales with different gradations), and quality of life (University Of Washington Quality of Life Questionnaire for Patients with Head andNeck Cancer) were assessed at baseline and at the end of the treatment. There were significant increases in both mean salivary flow rates (unstimulated: p = 0.0012; stimulated: p < 0.0001), mean pH values (p = 0.0002 and p = 0.0004), and mean score from the quality of life questionnaire (p < 0.0001). Low-level laser therapy seems to be effective to mitigate salivary hypofunction and increase salivary pH of patients submitted to radiotherapy for head and neck cancer, thereby leading to an improvement in quality of life.

This in vitro study aimed to analyze the effect of different parameters of phototherapy with low intensity laser on the viability of human dental pulp fibroblasts under the effect of substances released by bleaching gel. Cells were seeded into 96 wells plates (1 x 10³ cells/well) and placed in contact with culture medium conditioned by a 35 % hydrogen peroxide bleaching gel for 40 minutes, simulating the clinical condition of the in-office bleaching treatment. Cells cultured in ideal growth conditions served as positive control group (PC), and the cells grownin conditioned medium and non-irradiated served as negative control group (NC). Cells grown in conditioned medium were submitted to a single irradiation with a diode laser (40 mW, 0.04 cm²) emitting at visible red (660 nm; RL) or near infrared (780 nm; NIR) using punctual technique, in contact modeand energy densities of 4, 6 or 10 J/cm². The cell viability was analyzed through the MTT reduction assay immediately and 24 hours after the irradiation. The data was compared by ANOVA followed by the Tukey's test (p<0.05). The cell viability increased significantly in 24 hours within each group. The PC presented cell viability significantly higher than NC in both experimental times. Only the NIR/10 J/cm² group presented cell viability similar to that of PC in 24 hours. The phototherapy with low intensity laser in defined parameters is able to compensate the cytotoxic effects of substances released by 35 % hydrogen peroxide bleaching gel.

BACKGROUND:The photobiomodulation using the low-level laser therapy (LLLT) exerts a positive modulating effect on the synthesis of collagen in skeletal muscles and tendons. However, few studies have addressed this effect during the compensatory overload.

OBJECTIVE:Evaluate the effect of infrared laser on the deposition and organization of collagen fibers in muscle and tendon tissue during compensatory overload of the plantar muscle in rats.

MATERIALS AND METHODS:Wistar rats were submitted to bilateral ablation of the synergist muscles of the hind paws and divided in groups: Control, Hypertrophy, and Hypertrophy (H)+LLLT (780 nm, 40 mW, 9.6 J/cmand 10 s/point, 8 points, total energy 3.2 J, daily), evaluated at 7 and 14 days. Muscle cuts were stained with Picrosirius-Red and hematoxylin-eosin and tendon cuts were submitted to birefringence for determination of collagen distribution and organization.

RESULTS:After 7 days an increase was observed in the area between beam muscles in H+LLLT (25.45% ± 2.56) in comparison to H (20.3% ± 3.31), in mature fibers and fibrilis in H+LLLT (29346.88 μm ± 2182.56; 47602.8 μm ± 2201.86 respectively) in comparison to H (26656.5 μm ± 1880.46; 45630.34 μm ± 2805.82 respectively) and in the collagen area in H+LLLT (2.25% ± 0.19) in comparison to H (2.0% ± 0.15). However, after 14 days a reduction was observed in the area between beam muscles in H+LLLT (13.88% ± 2.54) in comparison to H (19.1% ± 2.61), in fibrils and mature fibers in H+LLLT (17174.1 μm ± 2563.82; 32634.04 μm ± 1689.38 respectively) in comparison to H (55249.86 μm ± 1992.65; 44318.36 μm ± 1759.57) and in the collagen area in H+LLLT (1.76% ± 0.16) in comparison to H (2.09 ± 0.27). A greater organization of collagen fibers in the tendon was observed after 7 and 14 days in H+LLLT groups.

CONCLUSIONS:Infrared laser irradiation induces an improvement in collagen organization in tendons and a reduction in the total area of collagen in muscles during compensatory atrophy following the ablation of synergist muscles.

Male infertility is a multifactorial syndrome associated with a wide range of pathological conditions affecting both the sexual and other body systems: endocrine, nervous, blood, and immune. Laser therapy is a form of modern physiotherapy that applies low-intensity laser irradiation (LILI) in various parts of the body. It is widely used in all areas of modern medicine due to its high efficiency, ease of use, the absence of contraindications and side effects. The authors reviewed the results of 171 studies investigating laser therapy, of which 93 were experimental (20 in Russian and 73 international publications), four clinical and experimental (all in Russian), 74 clinical (73 in Russian and 1 in English).Along with domestic literature, publications in Russian from Belarus, Georgia, Kyrgyzstan, Uzbekistan, and Ukraine were also reviewed. The review suggests that laser therapy should be used as much as possible in the management of male infertility not just due to high effectiveness, but also because of the lack of alternatives. For local application, optimal laser irradiation regimens are pulsed LILI of red (635 nm) and infrared (904 nm) spectra. For intravenous laser blood irradiation, the authors recommend alternating a continuous LILI with a wavelength of 635 nm (red spectrum) and 365 nm (ultraviolet spectrum).

PURPOSE:This paper aims to evaluate the effects of laser (660 nm) and light-emitting diode (LED) (670 nm) irradiation in the cheek pouch mucosa of hamsters with oral mucositis (OM) induced by chemotherapy (Che) with 5-fluorouracil (5-FU).

MATERIALS AND METHODS:In the preventive groups, the photobiomodulation was started 1 day before the drug administration and was performed every 48 h (Ia, IIa, Ib, and IIb). In the therapeutic groups (IIIa, IIIb, IVa, and IVb), the irradiations were started on the third day after the Che d(0) and was performed every 48 h. In both groups, animals were sacrificed 7 or 14 days after Che. In the positive control groups, the hamsters were subjected to Che but did not receive irradiation, and they were sacrificed in 7 days (Va) or 14 days (Vb). In the negative control groups, no procedures were done and the animals were sacrificed 7 days (Vc) or 14 days (Vd) after the experiment started.

RESULTS:The results indicated loss of body mass, xerostomia, and alopecia in the animals subjected to Che and the healing of OM to different degrees after the photobiomodulation treatment. Histologically, the positive control and experimental groups showed inflammation, predominately with lymphocytes and plasma cells, which tended to diminish with time. Epithelial atrophy, hyperemia, fibroblast proliferation, and vascular congestion were also observed at those intervals.

CONCLUSIONS:The best results were obtained from the preventive laser and LED photobiomodulation groups; both treatments were effective in diminishing the OM lesions.

CLINICAL RELEVANCE:A noninvasive and effective method with sparse side effects of OM would be desirable for use in cancer centers around the world.